A male still in possesion of his reproductive system who has sex with other peoples mothers. Such as from American Pie 1, 2, and Wedding the character Finch has sex with Stiflers Mom. He would be called an othermotherfucker because he had sex with someones elses mother.
Dude, that motherfucker isnt just a motherfucker, he's an othermotherfucker!
by Father Christmas November 27, 2004